1. Field
Embodiments disclosed herein are generally directed to systems and methods for synchronizing timing between wireless networking devices by exchanging frames including a timestamp.
2. Background
Wireless local area network (LAN) technology following the Institute of Electrical and Electronics Engineers (IEEE) 802.11 specification is commonly used for wireless connectivity amongst mobile computing devices due to its ability to economically satisfy the high bandwidth needs of the computing devices and the applications that run on the computing devices. According to the IEEE 802.11 specification (the “protocol”), a wireless Access Point (AP) may periodically transmit beacons that may include a timestamp field to other APs and/or network stations (STAs) to synchronize their local Timing Synchronization Function (TSF) timers with a TSF clock signal of the AP.
The timestamps transmitted by the APs may also be used for ranging, which is determining a position of an AP or STA by determining a round trip time or other timing value related to the transmission and reception of a timestamp by an AP. For certain types of ranging, it is desired that APs know the timing offsets of their own TSF timers and nearby APs. These timing offsets or timing delays may be periodically transmitted by an AP to nearby APs and STAs, and may be used by the STAs to determine a location relative to the transmitting AP.
Accordingly, there is a need for systems and methods for transmitting timestamps between APs and STAs that allow for nearby APs and STAs to determine a position with respect to the transmitting AP while maintaining a minimum of AP absence and traffic. In particular, there is a need for synchronizing the timing between APs and STAs that allow for minimal absences and collisions between the APs and STAs by randomly selecting new refresh intervals after each timestamp exchange.